1. Field of the Invention
This invention generally relates to a bicycle hub assembly with one way clutch that includes a pawl. More specifically, the present invention relates to bicycle hub assembly that includes an internal power transmission mechanism that has at least two power transmission paths where the pawl transmits torque in one power transmission path and does not transmit torque in another power transmission path.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One component that has been extensively redesigned is the bicycle hub assembly.
Many bicycle hub assemblies include an internal power transmission mechanism having two or more power transmission paths, where each path is defined by unique gear combinations through which torque is transmitted. One such bicycle hub assembly is disclosed in U.S. Pat. No. 6,641,500 (assigned to Shimano Inc.). In the disclosed bicycle hub assembly, the internal power transmission mechanism includes a plurality of planetary gears and ring gears that define a plurality of gear combinations or speeds (power transmission paths) that can be selected by a cyclist for transmission of torque.
Along one power transmission path torque is transmitted from a driver member through a pawl (a one way clutch) to a first ring gear. The ring gear transmits the torque through one of several selected ones of the planetary gear(s) and ring gear(s) at several different ones of the gear combinations.
Similarly, along another power transmission path torque is transmitted without the use of the pawl. Typically, while transmitting torque along the second of the two power transmission paths, the driver member and the first ring gear rotate at different speeds. Consequently, with torque transmitted along the second of the power transmission paths, the pawl ratchets between the driver member and the first ring gear making a clicking noise.
The noise made by the ratcheting movement of the pawl between the driver member and the first ring gear is undesirable to many cyclists. Some cyclists believe it creates drag, wastes energy and causes wear of the pawl and the first ring gear.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved pawl configuration that eliminate the noise made by a pawl when the driver member and the ring gear rotate a differing speeds. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.